Electrochromic devices prepared as laminates are known in the art. By way of example only, a laser cutting process may be used to prepare electrochromic (EC) panels on 2.2 mm annealed float glass from a large master panel that will be laminated onto a heat-strengthened or tempered outer lite. A process for manufacturing an electrochromic device laminate is described in PCT application PCT/US2011/027148, the disclosure of which is hereby incorporated by reference herein in its entirety.
It is believed that the use of annealed float glass for an EC application requires a careful treatment of the EC panel edge preparation in order to provide a strong enough edge to withstand in-service thermal stresses which are created by solar heating of the center of the panel. The analysis of stress generation and the increased protection afforded by use of laser cutting compared to conventional preparation methods are described in co-pending applications U.S. application Ser. Nos. 13/178,065 and 13/040,787, the disclosures of which are hereby incorporated by reference herein in their entirety.
Conventionally, in order to prepare an EC panel having a sufficiently strong edge to withstand in-service thermal stresses, laser cutting of the EC panel must begin outside of the finished panel. This is because the portion of the panel at which the laser cutting begins would be subject to possibly weakened stress resistance levels. FIG. 1 shows an example layout for cutting custom sized EC panels from a master panel 10. In FIG. 1, the master panel 10 is prepared to be cut into daughter panels 12, 14, 16, and 18. In order to cut apart panels 14 and 16, a laser cut must be performed along line 15. In order to perform such a laser cut, the laser cut should not begin in the area reserved for any of panels 12, 14, 16 or 18. Therefore, waste areas 11 and 19, on the border and in the middle of the master panel 10, must be reserved for beginning the laser cuts.
In the example of FIG. 1, the starter crack, or starter cut, for line 15 is approximately 15 mm from the intersection among panels 14 and 16 and waste area 19, and approximately 15 mm from the border between panel 12 and waste area 19. Thus, the waste area 19 is a ‘no-use’ region in the middle of the master panel 10, approximately about 20-25 mm in width. This would result in both a loss of useable area on the master panel as well as limit the customizability in daughter panel placement, and further reduces pattern yields.